This invention relates generally to microelectromechanical system switches.
Microelectromechanical system (MEMS) switches are mechanical switches that are fabricated using integrated circuit techniques at very small dimensions. Typically, MEMS switches use a tip configuration. The switch may consist of a cantilevered arm extending over a semiconductor substrate. Near the end of the cantilevered arm is a tip with a contact. The tip contact makes an electrical connection when the cantilevered arm is deflected towards the semiconductor substrate so as to electrically touch a contact formed on the substrate.
Other MEMS switches may use a beam instead of an arm. Here, too, a movable element over the substrate includes a protrusion that makes an electrical connection to a contact on the substrate when the beam is electrostatically deflected towards said substrate.
The manufacturing process flow for a tip-based switch may include timed etch steps. In high volume manufacturing, it is not desirable to work with timed etch processes since they may not be repeatable. The constituents that are used, such as acids, may change with time and etched layers may change from batch to batch. In high volume manufacturing, etch stop layers may be utilized to reduce the affect of timed etches. However, the use of etch stops also yields quite sensitive and complex process flows.
Thus, it would be desirable to provide a different type of MEMS switch.